cp's OEIS Frontend

A044818 Positive integers having distinct base-7 run lengths.

%I A044818 #13 Jan 04 2021 18:18:59
%S A044818 1,2,3,4,5,6,8,16,24,32,40,48,49,56,57,58,59,60,61,62,65,73,81,89,97,
%T A044818 98,106,112,113,114,115,116,117,118,122,130,138,146,147,155,163,168,
%U A044818 169,170,171,172,173,174,179,187,195,196,204,212,220,224,225,226,227,228
%N A044818 Positive integers having distinct base-7 run lengths.
%H A044818 David A. Corneth, <a href="/A044818/b044818.txt">Table of n, a(n) for n = 1..10000</a>
%e A044818 40=55_7 has a single run length of 2 and is in the sequence. 211=421_7 has three runs of length 1 as is not in the sequence. - _R. J. Mathar_, Jan 18 2018
%p A044818 rlset := proc(L::list)
%p A044818     local lset,rl,i ;
%p A044818     lset := [] ;
%p A044818     rl := 1 ;
%p A044818     for i from 2 to nops(L) do
%p A044818         if op(i,L) = op(i-1,L) then
%p A044818             rl := rl+1 ;
%p A044818         else
%p A044818             lset := [op(lset),rl] ;
%p A044818             rl := 1;
%p A044818         end if;
%p A044818     end do:
%p A044818     lset := [op(lset),rl] ;
%p A044818 end proc:
%p A044818 isA044818 := proc(n)
%p A044818     local dgs,rl;
%p A044818     dgs := convert(n,base,7) ;
%p A044818     rl := rlset(dgs) ;
%p A044818     if nops(rl) = nops( convert(rl,set)) then
%p A044818         true;
%p A044818     else
%p A044818         false;
%p A044818     end if;
%p A044818 end proc:
%p A044818 for n from 1 to 400 do
%p A044818     if isA044818(n) then
%p A044818         printf("%d,",n) ;
%p A044818     end if;
%p A044818 end do: # _R. J. Mathar_, Jan 18 2018
%Y A044818 Cf. A044813, A044814, A044815, A044816, A044817, A044818, A044819, A044820, A044821, A044822, A044823, A044824, A044825, A044826, A044827 (base 2 to base 16).
%K A044818 nonn,base
%O A044818 1,2
%A A044818 _Clark Kimberling_